Their fishing boat was going in circles at a speed of 15 knots, alerting those nearby that something was wrong. It happened seven miles south of Half Moon Bay off Martin's Beach in San Mateo County.
"Once you lose control of the helm, boats are designed to circle," said Sgt. John Gonzales with the San Mateo County Sheriff's Department. "It's a steering mechanism. It kind of pulls forward. It pulls to the right or left and it will stay in that circle."
The boat was a Boston Whaler, a popular fishing vessel known for being stable and seaworthy. The body of one of the two men on board was recovered soon after rescue crews arrived. The other is still missing, identified as Tuan "Tom" Tran who was believed to have been operating the boat. The Deputy Harbormaster believes neither was wearing a life jacket.
"I'm not sure if they would have survived in this situation," said Deputy Harbormaster Cary Smith. "But certainly they would have had their heads above water or long enough for somebody to have seen them."
Authorities let the boat run out of fuel. Deputies then towed it to Pillar Point Harbor. They're storing it as evidence and while they're not ruling anything out, it doesn't appear foul play was involved.
"The boat has already done a preliminary look through," said Gonzales. "Everything looks fine. It really looks like an accident but we just want to double check to make sure everything is fine."
No word on how long they'll be searching for Tran.
The Coast Guard is working through the night and the Harbormaster plans to rejoin the effort in the morning.